Cant find the air filter on my 19year old comfortair heater

Could be dirty filter or small return

sounds like a leak in the air stack or if coming from gas valve need new gas valve

The Comfortaire model 833 has a 3.15 amp fuse next to the power cord. Check to see if it has blown.

It very well could be a vac leak or a problem with the air filter box.
If you can make the sound happen sitting in park, have someone listen around the engine compartment with a section of heater hose while you operate the controls.

mr heater makes a whistling sound as gas escapes around the gasket of the ceramic heating elements, that is ,all around the outside edges of the ceramic heating elements.

You can find out exactly where the gas leak is , by pressing down on the outside edges of the ceramic elements with a big, long
slotted (flat bladed) screwdriver while mr heater is running and hot.

The screwdriver needs to be long enough so that you dont burn your hands [the longer & bigger the screwdriver, the better] & it does not hurt to wear heavy gloves too, because it gets very hot, very fast in front of mr heater.
The thicker the blade of the screwdriver is, the less chance of damaging the ceramic heating element because a thick bladed screwdriver will not concentrate all the pressure in just 1 tiny point.

You are not trying to crack the ceramic with a wood chisel.

Dont press down so hard that you break the ceramic heating element, start by pressing down gently and gradually increasing pressure until you notice a change in the whistle or sparks comming out of the heating element as loose carbon deposits
come out of the heating element and burn in the propaine flame.

When you press down on one edge ,the other opposite edge may come up slightly, resulting in loose carbon deposits escaping and burning as sparks.

also, you may not be pressing at the spot where the gas whistling is comming from and will need to move the screwdriver flat blade around the edges, here & there, to test for the effect of pressing down.

When you press down on the outside edge where the diamonds stop, while mr heater is whisteling, the whisteling will stop & mr heater will run quite. Sometimes, just pushing down with the screwdriver will stop the whisteling ,for a while,and maybe a good long while.

The big pain in the **** solution is to put a new gasket around the
ceramic heating elements, but there is no guarantee that the new gasket will not whistle.
Its a big ,nasty job, which I would rather not do--so I just push down with the screwdriver, to temporarly stop the whisteling, I guess it depends on how much the whisteling annoys you, as to if you want to go thru all the effort & expense of changing out the gaskets, without knowing if it will still whistle when you are done.

Im just a diy guy that has 3 big buddys I keep going for 4 yrs now.
I took one apart to look 4 the cause of the gas whistling, and then put it back together. Funny,it stopped whisteling & that was 3 yrs ago. I didnt put in any new parts.

It may help ,a lot ,to increase the pressure with which the Mr heater ceramic is pressed down against the gasket material.


This is accomplished by a heavy stainless steel wire that runs behind the ceramic heater element and goes through sheet metal
tabs on each side of the ceramic mounting frame.
You can bend the wire and the tabs,but only a little bit, and be very careful not to break the tabs because the tabs are not repairable, to increase the downwards pressure of the ceramic element against the gasket material. This may stop the gas whisteling--
its a try & see thing, a finicky adjustment, that sometimes works
& sometimes does not and sometimes, after a week or two, the ceramic might reseat itself against the gasket material and the whistling stop. Mine did stop whistling, but not until a couple of months after i did the job, due ,i think to reseating of the cermic against the gasket material. its try & see thing.


also ,a gas tank that has higher than average gas pressure may start gas whistling up but the whistling will stop after you have burned up the higher pressure of the propaine.

The wrong orifice was installed. Sta-Rite changed their blower configuration 3 years ago. Heaters older than that have a flat orifice that works with the older style blowers. Newer heaters are equipped with a tapered orifice. Mixing a flat with a new blower causes whistling. Mixing a tapered with an old blower causes whistling. Good luck!

this whine could also be coming from the gas valve itself. It is possible for the blower to make this noise as well. Make sure everything is in place and no hardware is missing, IE. screws, etc..

Go to comfortaire.com and then tech support. Down load manual from there.Russ

Its surely not turbo, its is somewhere a hole or leak in turbo air filter housing or air inlet pipe that is making noises when turbo sucks air. check the air pipes wheather they are fitted correctly. Take a keen look at air hose and close any hole with silver tape check the hose is fitted correctly in Turbo air filter housing (if not then it makes whistling noise when air is being sucked by turbo) . Clean all air filters and then give it a go.

The only possible explainations for your situation is that the air is either going around the filter and going straight to the coil or the air filter is on the wrong end of the furnace. The air should go through the filter before it goes through the furnace. If you can take the filter out and look at the coil, the air should be sucking into the furnace from that end, if it is blowing in your face, that is the problem. If all is ok with that then take a close look for where the air could be getting in without having to go through the air filter. Seal up any holes with duct tape or sheet metal or both.